Due to the environmental damage that has been inflicted on the planet as a result of the burning of fossil fuels, renewable energy has finally begun to be given significant attention, with many projects being developed around solar energy, wind energy, and tidal power. Of these alternative forms of energy, tidal power is arguably the most attractive, given that tidal flows are entirely predictable and constant, unlike wind or solar energy which are relatively intermittent and therefore less dependable.
However, harnessing tidal energy does provide its own challenges, in particular with respect to the installation, maintenance and retrieval of tidal power generators, for example hydro-electric turbines, which by the very nature of the operation of same must be located in relatively fast flowing tidal currents, and more than likely located on the seabed. In addition, in order to be economically viable these turbines must be built on a large scale. As a result the turbines and associated bases/supports are large components, and require heavy lifting and transport equipment in order to achieve both deployment and recovery thereof. The use of such heavy lifting equipment is normally a hazardous undertaking, and is rendered even more dangerous when this equipment is operated at sea under difficult and unsteady conditions.
The above processes are further complicated by an increasing shortage in the market of suitable vessels and equipment to perform such work and the extreme danger of engaging divers in high tidal flow sites.
DE102008032625 discloses a lifting device for a turbine generator unit that is adapted to lift a turbine off a seabed mounted base with the base being left fixed on the seabed. The device has an immersion component (1) comprising a transverse centering device (9) and a gripping device (10). The transverse centering device comprises movable enclosure elements that are opened outwardly while the lifting device is brought into position about the generator unit, and are then closed in order to centre the lifting device relative to a turbine generator unit (2). The turbine generator unit can then be lifted off the base, which remains in position on the seabed.
The present invention has therefore been developed with a view to simplifying the recovery of a base mounted hydroelectric turbine system, and in particular reducing the complexity and the time taken to effect recovery of the base and turbine, as a single unit, from the seabed.